refactor: refactors message dequeueing (#2810)

spec/lib/message_dequeuer/base_spec.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+module MessageDequeuer
+
+  RSpec.describe Base do
+    describe ".new" do
+      context "when given state" do
+        it "uses that state" do
+          base = described_class.new(nil, logger: nil, state: 1234)
+          expect(base.state).to eq 1234
+        end
+      end
+
+      context "when not given state" do
+        it "creates a new state" do
+          base = described_class.new(nil, logger: nil)
+          expect(base.state).to be_a State
+        end
+      end
+    end
+
+    describe ".process" do
+      it "creates a new instances of the class and calls process" do
+        message = create(:queued_message)
+        logger = TestLogger.new
+
+        mock = double("Base")
+        expect(mock).to receive(:process).once
+        expect(described_class).to receive(:new).with(message, logger: logger).and_return(mock)
+
+        described_class.process(message, logger: logger)
+      end
+    end
+  end
+
+end